A planetary system from the early Universe

Mar 27, 2012
Artist's impression of HIP 11952 and its two Jupiter-like planets. Image: Timotheos Samartzidis

A group of European astronomers has discovered an ancient planetary system that is likely to be a survivor from one of the earliest cosmic eras, 13 billion years ago. The system consists of the star HIP 11952 and two planets, which have orbital periods of 290 and 7 days, respectively. Whereas planets usually form within clouds that include heavier chemical elements, the star HIP 11952 contains very little other than hydrogen and helium. The system promises to shed light on planet formation in the early universe – under conditions quite different from those of later planetary systems, such as our own.

It is widely accepted that planets are formed in disks of gas and dust that swirl around young stars. But look into the details, and many open questions remain – including the question of what it actually takes to make a planet. With a sample of, by now, more than 750 confirmed planets orbiting stars other than the Sun, astronomers have some idea of the diversity among planetary systems. But also, certain trends have emerged: Statistically, a star that contains more “metals” - in astronomical parlance, the term includes all chemical elements other than hydrogen and – is more likely to have planets.

This suggests a key question: Originally, the universe contained almost no other than and helium. Almost all heavier elements have been produced, over time inside stars, and then flung into space as massive stars end their lives in giant explosions (supernovae). So what about planet formation under conditions like those of the very , say: 13 billion years ago? If metal-rich stars are more likely to form planets, are there, conversely, stars with a metal content so low that they cannot form planets at all? And if the answer is yes, then when, throughout cosmic history, should we expect the very first planets to form?

Now a group of astronomers, including researchers from the Max-Planck-Institute for Astronomy in Heidelberg, Germany, has discovered a that could help provide answers to those questions. As part of a survey targeting especially metal-poor stars, they identified two giant planets around a star known by its catalogue number as HIP 11952, a star in the constellation Cetus (“the whale” or “the sea monster”) at a distance of about 375 light-years from Earth. By themselves, these planets, HIP 11952b and HIP 11952c, are not unusual. What is unusual is the fact that they orbit such an extremely metal-poor and, in particular, such a very old star!

For classical models of planet formation, which favor metal-rich stars when it comes to forming planets, planets around such a star should be extremely rare. Veronica Roccatagliata (University Observatory Munich), the principal investigator of the planet survey around metal-poor stars that led to the discovery, explains: “In 2010 we found the first example of such a metal-poor system, HIP 13044. Back then, we thought it might be a unique case; now, it seems as if there might be more planets around metal-poor than expected.”

HIP 13044 became famous as the “exoplanet from another galaxy” – the star is very likely part of a so-called stellar stream, the remnant of another galaxy swallowed by our own billions of years ago.

Compared to other exoplanetary systems, HIP 11952 is not only one that is extremely metal-poor, but, at an estimated age of 12.8 billion years, also one of the oldest systems known so far. “This is an archaeological find in our own backyard,” adds Johny Setiawan of the Max Planck Institute for Astronomy, who led the study of HIP 11952: “These planets probably formed when our Galaxy itself was still a baby.”

“We would like to discover and study more planetary systems of this kind. That would allow us to refine our theories of . The discovery of the planets of HIP 11952 shows that have been forming throughout the life of our Universe”, adds Anna Pasquali from the Center for Astronomy at Heidelberg University (ZAH), a co-author of the paper.

Explore further: 'Perfect storm' quenching star formation around a supermassive black hole

More information: The work described here is being published as Setiawan et al., “Planetary companions around the metal-poor star HIP 11952”, in a forthcoming issue of the journal Astronomy & Astrophysics.

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User comments : 13

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that_guy
4.2 / 5 (5) Mar 27, 2012
Occams razor. If we have gas giants composed primarily of hydrogen and helium, then 'earlier' planets of a metal poor nature seem quite likely.

The only question is the detail of whether there's a point that it would be too metal poor to form planets, which has the logical fallacy of automatically assuming that not only do planets form by a very strict view of core accretion, they only form by this method, and no other methods.
kevinrtrs
1 / 5 (11) Mar 28, 2012
But look into the details, and many open questions remain including the question of what it actually takes to make a planet.
OOoooo! such honesty and openess - for once!

Like "that guy" implies: just because there are more planets to be found around metal-rich stars doesn't mean that metal-richness has anything necessarily to do with planet formation. The researchers have now discovered a simple case that goes against that kind of thought so they have to rethink their planetary formation once again.

HIP 13044 became famous as the exoplanet from another galaxy the star is very likely part of a so-called stellar stream, the remnant of another galaxy swallowed by our own billions of years ago.

What should really be troubling a lot of Big Bang theorists is the very fact that here you have an incredibly OLD star - composed of little more than H and He and YET it supposedly EXISTED so early in the Big Bang era! A lot of brainwork will be required to explain it.
Birger
5 / 5 (2) Mar 28, 2012
Jovian planets can form in metal-poor systems. But if the system was very metal-poor, there may not have been enough heavier elements to form proper terrestrial planets. Maybe smaller planetoids...but the Poynting-Reynolds effect will make small objects spiral into the star on time scales of bilions of years.
So maybe some Ceres-scale objects, but nothing bigger or smaller.
Thecis
1.4 / 5 (5) Mar 28, 2012
Why people have rated Kevinrtrs' post with 1 I don't know. He is quite right in that theories need to be adjusted when data becomes available that don't match up. That is the scientific method, starting with a 0 hypothesis....

On topic, could it be that very old stars have captured debris from something passing by, giving the first "push" into star formation. Most likely, planets formed in this manner would not be in the same equitorial plane. The article doesn't go into this and I dont know.
that_guy
5 / 5 (5) Mar 28, 2012
Why people have rated Kevinrtrs' post with 1 I don't know...

...The article doesn't go into this and I dont know.

People downrate Kevinrts because he's an asshole, and any logic or science in any of his statements is merely coincidental. If you actually have a discussion with him, you'll find that he's just here to throw stones at science and promote creationism or something like that.

I would assume that the article doesn't go in depth into the formation theories because:

a)There's more ground to cover than an article allows and
b)This conflicts with the favored planetary formation theory, and they don't yet have an adequately fleshed out explanation. Whether they modify the current, go with an alternate, or some other amalgamation of theories, they've got a good amount of work to do.

There are separate articles stating possible solutions, where this one is here more to outline the problem.
jsdarkdestruction
5 / 5 (2) Mar 28, 2012
Kevin gets 1's because we all know what lies behind hia comments. A very heavy creationist agenda.
Callippo
1 / 5 (4) Mar 28, 2012
The true is, the planetary system with mixed metallicity violates both Steady state, both Big Bang model (the worse for the later, the higher this metallicity is). In dense aether model the Big Bang nucleosynthesis and "proton decay" proceeds continuously at the many places of Universe, so that the very old remnants can be mixed with very new structures. The random walk mechanism just limits the probability of the mixing of parts of Universe, which are too different in their age. In my opinion, the number of dwarf clusters encircling the Milky Way galaxy could originate from remnants of galaxies, which are older, than the observable part of Universe.
Eoprime
5 / 5 (5) Mar 29, 2012
...violates both Steady state, both Big Bang model (the worse for the later, the higher this metallicity is).
Source?
In dense aether model the Big Bang nucleosynthesis and "proton decay"...
proton decay, proton decay, proton decay... doesn't seem to get real (i honestly tried it in front of a mirror!)
In my opinion
aka "I give an uneducated guess" ... please get lost in your Waterripples.
RealScience
3.7 / 5 (3) Apr 01, 2012
Kevin got a 1 for that comment because:
1) He totally misunderstood or deliberately misinterpreted that_guy's comment
2) He over-estimates the impact of this on planet-forming theory
3) It is not an isolated case of Kevin misinterpreting scientific findings
4) His misinterpretations are not random but always are in a young-earth-god-did-it-and-scientific-evidence-of-an-older-universe-is-always-wrong direction, leading many to believe that his misinterpretations are deliberate.
5) His current comment fits right in with that pattern, so nip it in the bud.
Modernmystic
5 / 5 (2) Apr 02, 2012
Kevin got a 1 for that comment because:
1) He totally misunderstood or deliberately misinterpreted that_guy's comment
2) He over-estimates the impact of this on planet-forming theory
3) It is not an isolated case of Kevin misinterpreting scientific findings
4) His misinterpretations are not random but always are in a young-earth-god-did-it-and-scientific-evidence-of-an-older-universe-is-always-wrong direction, leading many to believe that his misinterpretations are deliberate.
5) His current comment fits right in with that pattern, so nip it in the bud.


Who cares? Give him your 1 and be done with it already....

Kinedryl
not rated yet Apr 02, 2012
...violates both Steady state, both Big Bang model (the worse for the later, the higher this metallicity is.
Source?
It's elementary, my dear Watson. Originally, the universe contained almost no chemical elements other than hydrogen and helium. Almost all heavier elements have been produced, over time inside stars, and then flung into space as massive stars end their lives in giant explosions (supernovae). So what about planet formation under conditions like those of the very early universe, say: 13 billion years ago? If metal-rich stars are more likely to form planets, are there, conversely, stars with a metal content so low that they cannot form planets at all? And if the answer is yes, then when, throughout cosmic history, should we expect the very first planets to form?

As you maybe recognized, the source of my stance is the current article itself.
RealScience
5 / 5 (1) Apr 02, 2012

Who cares? Give him your 1 and be done with it already....

Thecis asked why everyone gave Kevin 1s, so I assume that Thecis cares.
Eoprime
not rated yet Apr 05, 2012
If metal-rich stars are more likely to form planets, are there, conversely, stars with a metal content so low that they cannot form planets at all? And if the answer is yes, then when, throughout cosmic history, should we expect the very first planets to form?


This is the correct question but it doesn't violate the BB model.
I would rather question the classicel planet formation model. I dont see a problem with small H/He balls in orbit around a much bigger H/He ball. (as TG points out in the first comment) But iam not an expert in the field.

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